Turbodrill



DeC- 5, 1967 J. R. loANEsYAN ETAL 3,356,338

TURBODR ILL 5 Sheets-Sheet 1 Filed June l5. 1965 Dec- 5, 1967 J. R.loANEsYAN ETAL 3,356,338

TURBODRILL Filed June 15, 1965 3 Sheets-Sheet 2 O rij/zgn .2.

DCC- 5, 1957 J. R. loANEsYAN ETAL 3,356,338

TURBODR I LL 5 Sheets-Sheet 5 Filed June l5, 1965 United States Patent3,356,338 TURBODRILL Jury Rolenovch Ioanesyan and Rolen Arsenievichloannesyan, Moscow, and Alexandr Nikolaevich Ovchinnkov, Ljubertsy,Moskovskoi Oblasti, U.S.S.R., assignors to VsesojuznyNauchno-Issledovatelsky Institut burovoi Tekhniki, Moscow, U.S.S.R.

Filed June 15, 1965, Ser. No. 464,129 6 Claims. (Cl. 253-3) ABSTRACT 0FTHE DISCLOSURE A turbodrill having a multistage turbine, a multistagebypass valve serving for adjusting the ilow of the drilling fluidthrough the turbine dependent upon the speed of its shaft, the turbineblades being so shaped that the angle of discharge of the drilling uidfrom the stator equals or approaches the inlet angle of the drillingiluid to the rotor while stationary with the angle of discharge of thefluid from the rotor in movement equa-ls or approaches the angle of theiluid inlet to the turbine stator.

The present invention relates to well drilling systems for boring deepWells in the surface of the earth with the object of nding oil, gas andother mineral resources, pertains more particularly to turbodrills withmultistage turbines and bypass valves. Known at present are turbodrillsof high rotational speed at a relatively low shaft torque. The reductionin speed and the increase in shaft torque of a turbodrill and the bitconnected thereto assist in a radical improvement of footage per bit,and thus of the total eiliciency of drilling.

The known types of turbodrills with multistage turbines and bypassvalves have only been capable of restricting the idle rotation of theturbine with the aid of said valves without, however, increasing theshaft torque or reducing the shaft rotational speed during drilling.

It is an object of this invention to eliminate said disadvantages.Accordingly, a principal object of the present invention is to provide aturbodrill with such a multistage turbine and such a bypass valve whichwill be capable of radically increasing the shaft torque of theturbodrill while decreasing its rotational speed.

These objects are attained by having, according to the invention, theturbine blades shaped so that the angles at which the drilling uidleaves the stator equal or approach the angles at which the uid passesonto the rotor at rest, while the angles of the fluid flow leaving theimmobile rotor equal or approach those at the inlet to the stator.

The bypass valve adjusting the circulation rate through the turbine ismade multistaged. Such an embodiment of the turbine serves for asubstantial decrease in pressure drop across the immobile rotor whileradically increasing said pressure drop as the rotational speed israised. This, in conjunction, with the bypass valve and working channelsof the turbine of a special shape and cross-section (in comparison toconventional type turbines) allows for increasing the ow rate of thedrilling fluid through turbine blades and sharply increasing the turbineshaft torque. Bypassing part of the fluid through the bypass valve thepressure drop with the turbine rotor in motion is maintained at the samevalue as that produced by the passage of the total stream through theturbine with the rotor immovable.

Each of the stages of the bypass valve is essentially a sleeve of aconical or a cylindrical shape made from an elastic material, such asrubber. A large diameter ball is inserted in said sleeve thus producingstresses in the 3,356,338 Patented Dec. 5, v1967 ICC and intended forthe discharge of drilling fluid into the borehole.

Embodiment of the present invention will now be described by way ofexample with reference to the accompanying drawings in which:

FIG. 1 is the turbodrill with the multistage turbine and r bypass valvehoused in a cylindrical casing above the turbine.

FIG. 2 is the turbodrill with the multistage turbine and bypass valvemounted in the hollow shaft of the turbine. FIG. 3 is a cross-sectionalview of the turbine blades shaped so as to prevent the surgingshockagainst said blades with the rotorvimmovable.

v turbine 1 comprising stators 2 accommodated in its housing 3 androtors 4 keyed to shaft 5, axial bearing 6, radial bearings 7 andmultistage bypass valve 8 mounted in cylindrical casing 9, said casingembodying channel 10 for the passage of drilling fluid to the turbine,and port 11 connected with the valve and intended for the discharge ofdrilling fluid into the borehole.

The blades of stators and rotors of the turbine are shaped `so (see FIG.3) that the discharge angle al, of the drilling fluid stream from thestator equals or approaches the angle l, of the lluid ilowing to therotor, while the discharge angle [32 of the fluid llowing from theimmobile rotor equals or approaches the inlet angle a0 of the flow tothe stator.

The drilling fluid is admitted through a drill string into casing 9 ofbypass valve 8, and thence through channel 10 is passed to the drillturbine. This brings rotors 4 and sha-ft 5 into rotation. Since theturbine blades are so shaped that the llow without surging shock throughsaid blades takes place with the rotor immovable, the increase in theturbine speed tends to build up pressure, as shown in FIG. 4. Thiseffect, however, does not take place as the bypass valve 8 comes intoaction, thus discharging a part of the drilling fluid into the boreholethrough port 11 bypassing the turbine. The drill turbine operates at aconstant pressure drop. T|he turbine embodied in the invention producesa low pressure drop at a low speed, and the rate of -uid owing throughturbine blades can thus be increased, which will raise the turbinetorque at a low rotational speed.

Torque M of such a turbodrill does not vary along a straight line, itfollows a concave curve which is very steep in the zone of slow speeds(as shown in FIG. 5) and flat in the zone of high speeds. Thus, such aturbodrill is capable of stable performance at a low speed, and viceversa, its performance being unstable at high speeds.

By increasing the weight on the bit, the turbine speed of such aturbodrill can be lowered to the value characteristic of rotarydrilling, while sharply increasing the shaft torque.

The multistage bypass valve 8 shown in FIG. 6 is formed by severalrubber sleeves 13 of a conical or a cylindrical shape, arranged inseries.. A ball bears upon a rest 14 of each of the sleeves 13. The balldiameter is selected so that the walls of sleeve 13 are under strain andstresses arerthus produced in the sleeve rubber,.said stressesrepresenting the pressure drop in the valve 8 stage. Such an embodimentof valve 8 ensures troublefree operation in handling abrasive fluidsunder high pressure, and its capacity to maintain the pressure constantwithin close limits, whereas the valve opening and closing pressuresremain constant.

The fluid admitted into the first stage of valve 8 stretches the wallsof sleeve 13 relative to ball 15 and passes into the next stage, where asimilar process takes place.

If the embodiment of the turbodrill includes a hollow shaft, the bypassvalve can be accommodated in the shaft bore, as shown in FIG. 2.11m thatcase the drilling fluid bypassed by the valve flows through bore 12 ofshaft 5 directly to the bit. l

A large diameter turbodrill is preferably built with a bypass valve 8mounted in the hollow shaft.

A small diameter turbodrill is preferably built with bypass valve 8housed in cylindrical casing 9 above the turbine.

What we claim is:

1. A turbodrill including: a multistage turbine; a multistage bypassvalve which serves to adjust the flow of the drilling fluid through saidturbine depending on the speed of its shaft; the blades of said turbinebeing of such a shape that the angle of discharge of the drilling fluidfrom the stator of said turbine equals or approaches the angle of inletof the drilling fluid to the rotor at rest, whereas the angle ofdischarge of the fluid from said rotor iny motion equals or approachesthe angle of the fluid inlet to the stator of said turbine.

2. A turbodrill including: a multistage turbine; a multisaidvimmobilerotor equals or approaches the inlet angle of the fluid flow to saidstator of the turbine.

3. The turbodrill as claimed in claim 2, wherein said elastic materia-lsleeve of the multistage valve is of a conical shape.

4. The turbodrill as claimed in claim 2, wherein said elastic materialsleeve of the multistage valve is of a cylindrical shape.

5. A turbodrill including a solid shaft multistage turbine; a multistagebypass valve which serves for adjusting the llow of the drilling fluidthrough said turbine depending on the speed of its shaft; the blades ofsaid turbine being of such a shape that the discharge angle of thedrilling fluid from the stator of said turbine equals or approaches theinlet angle of the drilling fluid to the rotor at rest, whereas thedischarge angle of the fluid from said immobile rotor approaches orequals the inlet angle of the fluid to said stator; a cylindrical casingmounted above said turbine to house said multistage bypass valve; saidcylindrical casing being provided with a channel for the passage of thedrilling fluid to said turbine, and a port connected with saidmultistage bypass valve which serves for discharging the fluid into theborehole.

6. A turbodrill including: a hollow shaft multistage turbine; amultistage bypass valve housed in the hollow shaft of said turbine andserving for the adjustment of the flow of the drilling fluid throughsaid turbine, depending on the speed of its shaft; the blades of saidturbine being of such a shape that the discharge angle of the drillinglluid from the stator of said turbine equals or approaches the inletangle of the drilling fluid to the rotor at rest, whereas the dischargeangle of the fluid from said immobile rotor equals or approaches theinlet angle ofthe fluid to said stator.

` FOREIGN PATENTS 122,425 1/ 1928 Switzerland.

EVERETTE A. POWELL, I R., Primary Examiner.

1. A TURBODRILL INCLUDING: A MULTISTAGE TURBINE; A MULTISTAGE BYPASSVALVE WHICH SERVES TO ADJUST THE FLOW OF THE DRILLING FLUID THROUGH SAIDTURBINE DEPENDING ON THE SPEED OF ITS SHAFT; THE BLADES OF SAID TURBINEBEING OF SUCH A SHAPE THAT THE ANGLE OF DISCHARGE OF THE DRILLING FLUIDFROM THE STATOR OF SAID TURBINE EQUALS OR APPROACHES THE ANGLE OF INELTOF THE DRILLING TO THE ROTOR AT REST, WHEREAS THE ANGLE OF DISCHARGE OFTHE FLUID FROM SAID ROTOR IN MOTION EQUALS OR APPROACHES THE ANGLE OFTHE FLUID INLET TO THE STATOR OF SAID TURBINE.